2020+ Ford Super Duty Upfitter Harness Extensions

Upfitter Extensions

Need more reach from your upfitter relay box? Our Upfitter Extensions use the same OEM-style connectors featured in our No-Crimp Solution, giving you clean, reliable plug-and-play access to each upfitter circuit — no cutting, no splicing required.

Each extension includes:
• 18 inches of wire with 12 inches of protective nylon sleeving
• Matching male and female connectors
• Heat-shrink solder connectors for secure, weather-resistant splices

Available Configurations

Harness extensions are offered in the same configuration options as our Upfitter No-Crimp Solution, ensuring consistent integration and a clean, system-level approach.

Available configurations include:

6-Wire
Includes all standard factory upfitter circuits.

7-Wire
Includes all standard factory upfitter circuits, plus:

• Ignition-hot circuit

8-Wire
Includes all standard factory upfitter circuits, plus:

• Ignition-hot circuit
• Always-hot 20-amp accessory power circuit

10-Wire
Full access configuration, including:

• All standard factory upfitter circuits
• Ignition-hot circuit
• Always-hot 20-amp accessory power circuit
• Both PTO (Power Take-Off) wires

This configuration structure keeps the system scalable and intentional, while allowing customers to choose the level of access that best matches their accessory needs.

Electrical Load Best Practice

Ford upfitter circuits allow for higher current capability, but most accessories draw far less than the maximum rating. For accessories that involve sustained high-current loads (such as onboard air compressors or large inverters), standard automotive practice is to use the upfitter switch as a control signal for a dedicated relay and fused power feed, rather than routing the full load through intermediate connectors.

This approach reduces heat at connection points, minimizes voltage drop, and provides the most reliable long-term solution.

For a clean and complete install, pair with our Grounding Solution.

Compatible with 2020–present Super Duty trucks.
Proudly made in the USA.